To count calories in homemade food, add up the calories of every raw ingredient that went into the pot, weigh the finished dish, and divide. That gives calories per gram of the cooked food, and any portion you weigh afterwards is one multiplication away. If the dish is cut into equal pieces, like a tray of lasagna, dividing the total by the number of pieces works as well.
In ChatRPE you type or say the ingredient list with amounts and the finished weight. It looks each ingredient up by name in public nutrition databases (Open Food Facts and, where configured, USDA FoodData Central), or by barcode if you photograph the packaging, then does the division and logs the portion you ate.
A worked example: one pot of chili
Here is a weeknight chili. The meat, oil and onion use USDA SR Legacy values for the raw food; the beans and tomatoes use typical can labels, which is what you would read off your own cans. Entries for the same food can disagree by around 10%: USDA's newer Foundation record for raw 90% lean beef lists about 185 calories per 100 g, not 176. Your own package label beats either.
| Ingredient, as it went in | Calories | Protein |
|---|---|---|
| 500 g ground beef, 90% lean, raw (176 per 100 g) | 880 | 100 g |
| 1 tbsp olive oil | 120 | 0 g |
| 1 onion, about 150 g raw (40 per 100 g) | 60 | 2 g |
| 2 cans kidney beans, drained, about 3 cups (label: 110 per half cup) | 660 | 42 g |
| 28 oz can crushed tomatoes, about 3.5 cups (label: 35 per half cup) | 250 | 10 g |
| Whole pot | 1,970 | 154 g |
Weigh the pot full, subtract the weight of the empty pot, and say the chili itself comes to 1,800 g. Then 1,970 ÷ 1,800 is about 1.09 calories per gram, or 109 per 100 g, with 8.6 g of protein per 100 g. A 400 g bowl is about 440 calories and 34 g of protein.
Water you add while cooking, and water that boils off, changes the weight of the pot but not its calories. That is why the finished weight has to be measured rather than taken from the recipe: a chili simmered an extra half hour holds the same 1,970 calories in fewer grams.
Why weighing the pot beats "it makes six servings"
The recipe says six servings, so a serving is 1,970 ÷ 6, or about 330 calories. That number is only right if the six bowls really are equal, and ladled bowls rarely are. Dish yourself a generous 450 g and log a sixth, and the entry reads 330 when the bowl held about 490.
One weighing of the finished pot removes that guesswork for every portion that follows, including the ones in the fridge. It also handles a household where people eat different amounts, since each bowl is weighed against the same per-gram figure.
Leftovers keep reducing as they sit and reheat, so a pot that weighed 1,800 g on Sunday may be denser by Wednesday. The per-gram figure from cooking day will slightly undercount a thickened leftover. For most goals that error is small; if you are on a tight cut and the dish has clearly reduced, weigh what is left and recalculate.
Raw or cooked: log the state you weighed
Most homemade-calorie mistakes come from weighing food in one state and looking it up in the other. Meat loses water as it cooks, so cooked meat has more calories per gram. Rice and pasta absorb water, so cooked grains have far fewer. These are USDA FoodData Central values:
| Food, per 100 g | Raw or dry | Cooked |
|---|---|---|
| Chicken breast, skinless | 120 kcal | 165 kcal (roasted) |
| White rice, long-grain | 365 kcal | 130 kcal |
| Pasta, enriched | 371 kcal | 158 kcal |
Weigh 150 g of cooked chicken and log it as raw chicken, and the entry says 180 calories for about 250. Weigh 200 g of cooked rice and log it as dry rice, and it says 730 for about 260. Neither is a small rounding error.
The simplest rule is to weigh ingredients before cooking, when you are building a recipe, and to say "raw" or "dry" when you describe them. When you only have cooked food in front of you, say "cooked" so the lookup matches. ChatRPE's food search returns up to five matching entries, so check that the one it used describes the state you weighed.
Count every spoon of fat that went in
Oil and butter are the ingredients people skip, and they are the densest things in the pan. A tablespoon of olive oil is about 120 calories and a tablespoon of butter about 100. In the chili above, the single tablespoon of oil is 6% of the pot. A stir-fry started with three tablespoons carries 360 calories that never look like food.
Count what you put in. If you brown mince and pour the fat off, the true number is a little lower than the log, which is a better direction to be wrong in than the reverse. The eating out guide covers the same hidden fat on restaurant plates, where you cannot see the pan at all.
Without a food scale
A kitchen scale makes this easiest, but you can get a usable number without one.
- Cut baked dishes into equal pieces. A tray of lasagna or a loaf of banana bread divides cleanly by count, and the total from the ingredient list is all you need.
- Measure soups and stews by volume. Ladle the finished pot into a measuring jug or count cups as you portion it into containers, then divide the total by the cups.
- Portion straight into containers on cooking day. Five matching meal-prep boxes from one pot make each box a fifth, with no later guessing.
- Use the labels you already have. Packaged ingredients list a serving size in cups or grams, so "half the 500 g bag of pasta, dry" is precise without weighing anything.
A volume or piece count is less exact than grams, so treat it as an estimate. For the dishes you cook every week, the calorie tracker guide explains why repeated staples are where extra precision pays off.
Log it once, then log the next bowl in one sentence
The work happens the first time you make a dish. Give ChatRPE the ingredient list and the finished weight, ask for calories and protein per 100 g, and ask it to log your portion with the recipe name in the entry. A photo of the recipe card or a list typed from memory both work; for packaged ingredients you can send barcode photos instead of names.
After that, "log another 350 g bowl of Sunday's chili" is a complete message. The chat can search your saved entries by keyword, find the earlier chili entry, and scale it to the new weight. If you cook the same recipe again with a different amount of meat or oil, give it the new list so the old per-gram figure does not carry over.
For a week of batch cooking, the meal planning guide covers turning these dishes into a plan and a shopping list. Once the portions are logged, a question like "what has my average daily protein been this week" reads from the same entries.
Frequently asked questions
How do I calculate calories in a homemade meal?
Add the calories of every ingredient as it went into the pot, using raw or dry weights and including the oil. Weigh the finished dish without its container. Divide the total calories by the finished weight to get calories per gram, then multiply by the weight of your portion. If the dish is cut into equal pieces, divide the total by the number of pieces instead.
Should I weigh food raw or cooked when counting calories?
Either works, as long as the nutrition entry matches the state you weighed. Raw weights are more consistent because cooking time changes how much water meat loses and grains absorb. If you weigh cooked chicken, rice or pasta, use a cooked entry for it. Mixing the two is the most common reason a home-cooked log is wrong by a third or more.
How do I count calories in soup or a casserole?
Total the ingredients, then weigh or measure the finished soup or casserole. For soup, weighing the pot or counting cups as you ladle it out gives a per-cup or per-gram figure. For a casserole or lasagna, cutting it into equal pieces is usually enough. Added stock or water changes the volume, not the calories, apart from whatever the stock itself contains.
Does cooking change the calories in food?
Cooking mostly changes the weight, not the calories. Meat loses water and grains gain it, so calories per gram move a lot while the calories in the whole portion stay close to the same. Fat that renders out and gets poured away is the main real loss. Oil, butter and sauces added during cooking are real calories and need to be counted.
How do I count calories in a recipe without a scale?
Use the package labels for amounts, then divide the dish by pieces, cups or containers. A tray cut into eight squares, or a pot portioned into five matching boxes, gives a usable per-portion number. Treat it as an estimate, and if the same dish is a staple, weigh it once to check how far off the estimate runs.
Can ChatRPE remember a recipe I cook often?
It saves the portion you logged, recipe name and numbers included, to your history, and chat can search that history by keyword. Asking for "another bowl of the chili" lets it find the earlier entry and scale it to the new weight. If the recipe changes, send the new ingredient list so it recalculates rather than reusing the old figure.
How accurate is counting calories in home cooking?
Usually more accurate than any other meal you do not get from a package, because you know every ingredient and the amount of oil. Remaining error comes from database values, uneven portions and cooking losses, so a well-built recipe log is a close estimate rather than an exact figure. Judge it by whether your weight trend moves as expected over a few weeks.